Hey - I was curious if anyone had information on pros/cons of a gravity fed power washer VS installing a water pump to pull the water from a tank for my mobile detailing trailer.

I have just purchased a 6x12 trailer that I am looking to use for as a mobile detailing unit and am in the process of purchasing equipment.

I want to run two 330 gallon IBC tanks (40"x48"x53", raised some inches on a skid) with a pressure washer and a generator, but I don't know how well electric/gas powered pressure washers pull water by gravity or if I will be needing a water pump.

If gravity is fine then would I have to use a gas powered power washer for gravity fed tanks or would electric be fine?
Same thing if a water pump is needed would I need a gas powered vs electric?

Any info/insight is greatly appreciated!